1. Field of the Invention
The invention is directed to a parking brake actuating device for a parking brake arrangement in a motor vehicle, the device comprising a rotary lever arrangement in operative connection with a compensation device providing an idle path and a restoring element for controlling the rotary lever arrangement, which in turn controls the engagement of a blocking member with a counter-blocking member of the parking brake arrangement.
2. Description of the Related Art
Parking brake arrangements are known in general in vehicles with hydrodynamic torque converters and serve to prevent the vehicle from rolling away accidentally when the engine is turned off by blocking the transmission output shaft which is connected with the driving wheels so as to be fixed with respect to rotation relative to them. Parking brake arrangements are also applied in electrically driven motor vehicles. As a rule, these vehicles do not have a standard transmission because the electric engine which is provided for driving can deliver a usable torque over an appreciably broader range of speeds in any driving situation compared to an internal combustion engine. Here, also, it is necessary to block a drive shaft which is connected with the driving wheels so as to be fixed with respect to rotation relative to them in order to prevent the parked vehicle from rolling away accidentally. This drive shaft can be the rotor shaft of the electric engine, for example. Vehicles of the type mentioned above usually have a selector lever for selecting the parking gear and different driving gears, this selector lever being in an operative connection with the parking brake arrangement. The position of the selector lever selected by the driver is locked by a locking device until another gear is selected.
There are already numerous known arrangements for blocking a shaft which is connected with the driving wheels so as to be fixed with respect to rotation relative to them and which generally comprises a locking member and counter-locking member. However, such arrangements are not the subject of the invention. The parking brake actuating device discussed herein is directed instead at means for the articulation of the blocking device.
A parking brake arrangement with a parking brake actuating device of the type mentioned above is known, for example, from DE 195 33 141 C1. The parking brake arrangement described therein comprises a toothed parking brake wheel and, further, a pawl which is rotatably supported so as to be fixed with respect to the housing and which has a projection that can engage in a gap in the parking brake wheel and accordingly prevents the vehicle from rolling by means of a positive engagement. The articulation of the pawl is carried out by means of a cam roller located at a lever of a rotary lever arrangement, wherein the other lever of the rotary lever arrangement is in an operative connection with the selector lever with a Bowden cable or rod linkage, a tension spring being arranged in the force flow of the latter. The rotary lever arrangement further comprises a torsion spring or leg spring which is arranged at this rotary lever arrangement and at the housing. When the driver moves the selector lever into the parking position, the force is directed to the pawl via the elements arranged in the force flow and the projection is pressed into a gap in the blocking wheel. The leg spring is tensioned at the same time. When a tooth of the blocking wheel and the projection of the pawl are radially across from one another during actuation of the selector lever and the pawl can not lock in, the tension spring expands while providing a free travel or an idle path. When the selector lever is moved from the parking gear to a driving gear, the tension spring relaxes again and the rotary lever arrangement is moved back into its initial position again by the restoring action of the leg spring with assistance from another leg spring connected with the pawl.
In principle, the parking brake actuating device described above satisfies the functional requirements demanded of it. However, developments in automotive engineering have aimed increasingly at the use of ready-to-install component assemblies. In this way, mounting to the vehicle is simplified, the range of uses for the respective component assembly is expanded to different vehicles and, further, ease of maintenance is improved. In this respect, the described parking brake actuating device has disadvantages. For example, numerous individual components of the parking brake actuating device are arranged in the interior of a housing, e.g., a transmission casing or housing of an electric motor, in such a way that they must be mounted in the installed position before the corresponding housing is assembled. Therefore, maintenance or repair of the parking brake actuating device requires time-intensive and cost-intensive labor. Another disadvantageous feature is the locking arrangement which is in an operative connection with the parking brake actuating device. Although closely connected with respect to function, the parking brake actuating device and the locking arrangement are fitted to different mounting locations in the vehicle. This feature also disadvantageously impedes application of a particular embodiment form of the above-mentioned type of parking brake actuating device to different types of vehicles, for example, vehicles of a platform.
On this basis, it is the object of the invention to provide a compact, universally applicable parking brake actuating device which is easy to mount and which overcomes the disadvantages of the prior art mentioned above.
According to the invention, the rotary lever arrangement has a rotary lever input part and a rotary lever output part, wherein the idle path of the compensation device can be constructed so as to be in an operative connection between the rotary lever input part and the rotary lever output part.
The invention is based upon the main idea that the rotary lever arrangement which to was formerly constructed in one part now comprises multiple parts, namely, a rotary lever input part and a rotary lever output part, and that the latter are arranged and constructed in such a way that, when necessary, a torque introduced via the rotary lever input part is conducted to the rotary lever output part not immediately but with a time delay by means of providing an idle path. This requirement occurs when a working operative connection can temporarily not be established between the blocking member and counter-blocking member of the parking brake arrangement because of their relative position.
In an advantageous further development of the invention, the rotary lever input part and/or rotary lever output part are/is mounted so as to be rotatable in a flange component part. With this flange component part, the parking brake actuating device can be fitted to a mounting location provided for it and can be used to transmit torque from the rotary lever input part to the rotary lever output part.
It is further advantageous that the flange component part is arranged so as to be stationary with respect to a housing of the parking brake arrangement. The position of the parking brake actuating device relative to a blocking member and counter-blocking member of the parking brake arrangement is accordingly defined and a reliable operation of the parking brake arrangement is ensured.
In another advantageous construction, the housing has a through-opening at least for the rotary lever output part. Accordingly, at least one part of the parking brake actuating device can be inserted into the housing from the outside. This construction constitutes a significant advantage over previous parking brake actuating devices because it is now possible to mount this device after the housing has been assembled. Enormous savings in cost and time can also be achieved in this way when maintenance and repair work is required.
The rotary lever input part advantageously has a shaft portion which is mounted inside the flange component part so as to be swivelable.
The rotary lever input part is preferably in an operative connection with a manual actuator or an actuator that is supplied by external energy. This actuator carries out an adjusting movement depending on a control command and introduces torque into the rotary lever input part.
The actuator supplied by external energy is preferably constructed as an electric motor and comprises means for determining a switching position of the rotary lever input part. In this case, the adjusting movement can be carried out immediately practically without a time delay after a control command is given. When the actuator has an angle sensor or displacement sensor, the switching position of the rotary lever input part can be determined directly from this detected position.
In a preferred arrangement, the electric motor actuator is arranged coaxial to the axis of rotation of the rotary lever input part. In this case, it is possible to adapt the electric motor actuating member in a particularly simple manner, e.g., by means of a simple sleeve which connects the rotary lever input part with the shaft of an electric motor.
In a further advantageous step, the idle path of the compensation device is provided by the rotary lever input part or the rotary lever output part. For this purpose, the respective part is constructed in a corresponding manner. Alternatively, it is also possible to arrange the idle path in such a way that it can not be allocated to either of the two parts mentioned above, but rather only results from cooperation with other elements.
In a particularly advantageous construction, the two rotary lever parts have coupling surfaces which determine the idle path and enable a transmission of the switching movement from the rotary lever input part to the rotary lever output part. The coupling surfaces of the one rotary lever part accordingly constitute boundaries of the idle path on both sides, whereas those of the other respective rotary lever part function as drivers.
At least one of the two parts advantageously has a segment-shaped cutout in circumferential direction to provide the idle path. The coupling surfaces can accordingly be produced in a particularly simple manner with respect to manufacturing technique.
It is further advantageous that the idle path is limited by a stop element during a relative movement of the rotary lever input part and rotary lever output part.
The stop element is preferably formed by a pin which projects radial to the longitudinal axis of one of the two rotary lever parts. This construction best performs the function and is easily realized.
Another essential feature of the invention consists in that the restoring element of the compensation device is anchored at the rotary lever output part and at the rotary lever input part. In this way, the invention advantageously sets itself apart from the solution known from the prior art.
The restoring element of the compensation device is advantageously formed by a spring. A leg spring, for example, is suitable for this purpose.
The rotary lever input part and the rotary lever output part are advantageously connected with one another such that they are secured axially. This step for allocating the parts mentioned above also proves advantageous for a simple assembly.
In a particularly advantageous construction, the rotary lever output part is constructed as a shaft and is arranged coaxial to the rotary lever input part.
In another construction, the rotary lever output part has a roller lever with a freely rotatable roller. The rotary lever output part can accordingly be brought into an operative connection with a blocking member of the parking brake arrangement, for example, a locking pawl, in a particularly simple manner.
In another construction, the rotary lever arrangement has a locking arrangement by which a plurality of defined switching states may be fixed based on the preset of a selector device. This construction likewise clearly sets itself apart from the prior art in an advantageous manner. In this way, functional units which are connected with one another with respect to function are also joined with respect to location, that is, in a functional unit.
The locking arrangement advantageously comprises at least one pretensioned locking device which enters into connection with a counter-locking device when a defined switching state is reached.
The at least one locking device can advantageously enter into connection with one of a plurality of counter-locking devices arranged on a common pitch circle at the flange component part or at the rotary lever input part. Accordingly, one or more defined switching states can be realized by a rotational movement of the rotary lever input part relative to the flange component part.
In a still more advantageous variant, a plurality of locking devices are arranged at the flange component part or rotary lever input part at an axial distance from one another and enter into connection, respectively, with one of a plurality of counter-locking devices which are arranged on the other respective part so as to be offset axially and in circumferential direction. In this way, a plurality of defined switching states can be occupied successively by means of the locking arrangement with only a relatively slight swiveling of the rotary lever input part.
The rotary lever arrangement advantageously has means for sensing a position of the rotary lever output part relative to the rotary lever input part. When the position of the rotary lever input part is known based on the fact that a determined locking position is occupied, as was described above by way of example, and the movement of the rotary lever output part is sensed in addition, it can be deduced from this information whether or not a blocking member engages with a counter-blocking member of the parking brake arrangement.
The construction according to the invention makes it possible for the rotary lever arrangement to be preassembled as a constructional unit and to be positioned in operative connection to the blocking member from the outside through the through-opening of the housing. In this way, a considerable simplification is achieved compared with the assembly of a known parking brake actuating device.
At least one of the rotary lever parts advantageously has a stepped contour, wherein a shoulder of the step constitutes an axial bearing surface for supporting the rotary lever input part relative to the rotary lever output part.
The parking brake actuating device according to the invention will be described in the following with reference to different embodiment examples. In the description of the individual embodiment examples, identical or analogous parts are designated by the same reference numbers supplemented by the letters a, b, c or d and only differences relative to previously discussed embodiment examples are described. To this extent, reference is had expressly to the description of the embodiment example or embodiment examples already discussed.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.